Calculate the Cd of your car - Instructable

[trebuchet03]

Originally Posted by usedgeo

This is not the answer to your question but it is almost relevant. Marks Standard Handbook stated that the rule of thumb for trains was that a 100 lb force could accelerate 1 ton of train 1 mph/sec. This figure was including the angular acceleration of the wheels.

That's a really goofy unit... At least, something I'm very not used to and required an extra thought step to comprehend (and now can see how it's useful) So I checked the number (assuming no wheel slip and no wheel-mass losses) just for fun...

1 ton ~ 62slug
100/62= 1.61 ft/s*s --> 5806 ft/hr*s --> 1.0968 mile/hr*s --> 1.0968 mph/s

Something tells me the momentum in a train bogie is greater than the momentum in car wheels Angular momentum for a wheel will be the wheel's moment of inertia * angular velocity. This will vary quite a bit depending on wheel size, material and shape. So, if you want to include angular momentum -- first find it - then add to 100 in that poorly described equation above (the easy way to do unit conversion is to type 1.61 ft/s^2 to mph/s into google ).